moka/lib/parser.c

#include "parser.h"


#define MK_TRY(func) parser_try(self, func)

void parser_init(struct parser* self, struct lexer* lexer)
{
    assert(self);
    assert(lexer);
    self->lexer = lexer;
}

void parser_free(struct parser* self)
{
    assert(self);
}

struct node* parser_try_new_parse(struct parser* self)
{
    assert(self);
    return MK_TRY(parser_try_new_root);
}

struct node* parser_try(struct parser* self,
                        struct node* (*rule)(struct parser*))
{
    assert(self);
    assert(rule);
    struct lex_context ctx = lexer_state(self->lexer);

    struct node* node = rule(self);
    
    if (node == NULL)
    {
        lexer_restore(self->lexer, ctx);
    }

    return node;
}

struct node* parser_try_new_root(struct parser* self)
{
    assert(self);
    struct node* root = malloc(sizeof(struct node));
    node_init(root, NODE_ROOT, NULL, self->lexer->context.line);

    while (!lexer_end(self->lexer))
    {
        struct node* expr = MK_TRY(parser_try_new_expr);

        if (!expr && !lexer_end(self->lexer))
        {
            printf("not at end: %c\n", self->lexer->source[self->lexer->context.cursor]);
            node_free(root);
            free(root);
            return NULL;
        }

        node_add_new_child(root, expr);
    }

    return root;
}

struct node* parser_try_new_expr(struct parser* self)
{
    assert(self);

    if (lexer_next_is(self->lexer, TOKEN_OPAR, 0))
    {
        return MK_TRY(parser_try_new_call);
    }

    return MK_TRY(parser_try_new_atom);
}

struct node* parser_try_new_call(struct parser* self)
{
    assert(self);

    if (!lexer_next_is(self->lexer, TOKEN_OPAR, 0))
    {
        return NULL;
    }

    lexer_skip(self->lexer, TOKEN_OPAR);

    struct node* target = MK_TRY(parser_try_new_expr);
    
    if (!target)
    {
        return NULL;
    }

    struct node* call = malloc(sizeof(struct node));
    node_init(call, NODE_CALL, NULL, target->line);
    node_add_new_child(call, target);

    while (!lexer_next_is(self->lexer, TOKEN_CPAR, 0))
    {
        struct node* arg = MK_TRY(parser_try_new_expr);

        if (!arg)
        {
            node_free(target); free(target);
            node_free(call); free(call);
            node_free(arg); free(arg);
            return NULL;
        }

        node_add_new_child(call, arg);
    }

    if (!lexer_next_is(self->lexer, TOKEN_CPAR, 0))
    {
        node_free(target); free(target);
        node_free(call); free(call);
        return NULL;
    }

    lexer_skip(self->lexer, TOKEN_CPAR);
    return call;
}

struct node* parser_try_new_atom(struct parser* self)
{
    assert(self);

    if (lexer_next_is(self->lexer, TOKEN_FLOAT, 0))
    {
        struct node* node = malloc(sizeof(struct node));
        struct token* tok = lexer_try_new_next(self->lexer);
        assert(tok);
        node_init(node, NODE_FLOAT, tok,
                  self->lexer->context.line);
        return node;
    }

    if (lexer_next_is(self->lexer, TOKEN_INT, 0))
    {
        struct node* node = malloc(sizeof(struct node));
        struct token* tok = lexer_try_new_next(self->lexer);
        assert(tok);
        node_init(node, NODE_INT, tok,
                  self->lexer->context.line);
        return node;
    }

    if (lexer_next_is(self->lexer, TOKEN_BOOL, 0))
    {
        struct node* node = malloc(sizeof(struct node));
        struct token* tok = lexer_try_new_next(self->lexer);
        assert(tok);
        node_init(node, NODE_BOOL, tok,
                  self->lexer->context.line);
        return node;
    }

    if (lexer_next_is(self->lexer, TOKEN_STRING, 0))
    {
        struct node* node = malloc(sizeof(struct node));
        struct token* tok = lexer_try_new_next(self->lexer);
        assert(tok);
        node_init(node, NODE_STRING, tok,
                  self->lexer->context.line);
        return node;
    }

    if (lexer_next_is(self->lexer, TOKEN_SYMBOL, 0))
    {
        struct node* node = malloc(sizeof(struct node));
        struct token* tok = lexer_try_new_next(self->lexer);
        assert(tok);
        node_init(node, NODE_SYMBOL, tok,
                  self->lexer->context.line);
        return node;
    }

    if (lexer_next_is(self->lexer, TOKEN_IDENT, 0))
    {
        struct node* node = malloc(sizeof(struct node));
        struct token* tok = lexer_try_new_next(self->lexer);
        assert(tok);
        node_init(node, NODE_IDENT, tok,
                  self->lexer->context.line);
        return node;
    }
    

    return NULL;
}